Endings

WARNING: SPOILERS ARE POSTED BELOW. DO NOT READ FURTHER IF YOU DON'T WANT TO KNOW THE ENDING.

Shin Megami Tensei IV has a total of four endings that can be taken. Three of the four endings are based completely on Alignment, which is measured by the choices you make during several Main and Challenge Quests. The fourth ending is a sort of bad ending for selecting the wrong choice near the final missions.

Law Ending

This ending can be reached by choosing the good, Law choices during quests. Jonathan will side with all Law choices, making it easier to recognize which is which.

The Protagonist chooses to go with Jonathan and protect the Eastern Kingdom of Mikado. Jonathan fuses with the Herald demons that are in Mikado (Raphael, Uriel, Gabriel, and Michael) to become Merkabah. Together, they go to defeat Lucifer in his palace to clear the world of demons and the "filth" of Tokyo.
Once Lucifer is killed, they activate the Yamato Reactor, creating a black hole that kills all living things in Tokyo, including themselves. The people in the Eastern Kingdom of Mikado live peaceful and erect a statue of the Protagonist in the courtyard.Spoiler - Click to see/hide

Chaos Ending

This ending can be reached by choosing the bad, Chaos choices during quests. Walter will side with all Chaos choices, making it easier to recognize which is which.

The Protagonist chooses to go with Walter to destroy the Status Quo. Walter fuses with Lucifer, who was previously disguised as the young girl Hikaru, and they head to the Eastern Kingdom of Mikado. Before they can reach it, they must defeat Merkabah in his palace to break down the barrier in Naraku.
Once Merkabah is killed, they open up Naraku to the Eastern Kingdom of Mikado, allowing demons and humans to "live" together. Everyone is given freedom, but this also fills the world with Chaos. The Protagonist and Lucifer look about the burning Kingdom from the rooftop. Lucifer, as Hikaru, tells the protagonist the people secretly wish for a new king. She asks the protagonist if he will be the one to rise and rule them.Spoiler - Click to see/hide

Neutral Ending

This ending is the toughest to reach. Neutral dialogue choices must be made, which are usually ignoring the problem at hand. In addition to that, several Challenge Quest must be completed:

Nihilistic Ending

This is the easiest ending to get, and can be obtained while on either of the three Alignment paths. At the end of The Tokyo Kingmaker, choose to "Return the world to nothing." Destroy the Yamato Reactor to end the game.

After destroying the Yamato Reactor, a black hole will form. This black hole will destroy the entire world, ending the game.Spoiler - Click to see/hide